Metastability of gold-carbonyl cluster complexes, Au _N(CO) _M ^-

Abstract:

Smaller gold-cluster anions, typified by Au ₇ ^-, adsorb multiple CO molecules in a high-pressure, room-temperature flow-reactor, tending toward previously unknown saturation compositions, Au₇(CO) ₄ ^-. The weakness of the gold-carbonyl adsorption bond is evidenced indirectly by the high CO partial pressure required and more directly by the high probability of fragmentation in the field-free flight region of the reflectron-type time-of-flight mass spectrometer. The analysis of this metastability reveals that the actual distribution f_N,M of products Au₇(CO) _M ^- in the reactor may be highly non-statistical, e.g. with only even-M species present.